reflection/refraction filter AOV?

[Derek Flood]

It appears that there is no "reflection filter" AOV for the AlSurface. I suppose I could derive it in Nuke by dividing the indirect_diffuse_raw and the  indirect_diffuse AOVs. Would that be the recommended way?

Next, how would I get a "refraction filter" AOV?

thanks!

[Anders Langlands]

Hi Derek, I"m not sure what you're after. What is reflection filter and refraction filter exactly?

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[Derek Flood]

Hi Anders,

The "reflection filter" is multiplied with the raw reflections to get the reflection (raw reflection * reflection filter = reflection. Or said in Arnold AOVs: raw indirect spec * indirect spec "filter" = indirect spec). So raw reflections give the full reflection of objects reflecting in the scene, and the reflection filter shows how much of that reflection should come through in the composite. In other words, the filter defines the strength of the reflection, while the raw image defines what is being reflected in the image.

Similarly the refraction filter is essentially the refraction amount. So objects with none would be black and objects with full refraction would be white. Raw refraction * refraction filter = refraction.

As to why I need these... I'm trying to see if I can use the Vray Denoiser tool in Nuke to work with Arnold AOVs, and refraction filter and reflection filter are two of the passes that I was not sure how to generate (well, refraction filter anyway. I'm pretty sure I can derive a reflection filter in Nuke).

[Anders Langlands]

What you're calling reflection filter is just (Specular Strength * Specular Color) in alSurface. So just take whatever you have plugged in there and output in one of the IDs.